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| author | Will Deacon <will.deacon@arm.com> | 2012-07-06 18:46:45 +0400 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-07-09 20:42:23 +0400 |
| commit | 923df96b9f31b7d08d8438ff9677326d9537accf (patch) | |
| tree | 3df937a0431a2ae0500ae011f5742a28611490fa /arch/arm/kernel | |
| parent | f8f5701bdaf9134b1f90e5044a82c66324d2073f (diff) | |
| download | linux-923df96b9f31b7d08d8438ff9677326d9537accf.tar.xz | |
ARM: 7451/1: arch timer: implement read_current_timer and get_cycles
This patch implements read_current_timer using the architected timers
when they are selected via CONFIG_ARM_ARCH_TIMER. If they are detected
not to be usable at runtime, we return -ENXIO to the caller.
Furthermore, if read_current_timer is exported then we can implement
get_cycles in terms of it for use as both an entropy source and for
implementing __udelay and friends.
Tested-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
| -rw-r--r-- | arch/arm/kernel/arch_timer.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index dd58035621f7..dbbeec4f06e2 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c @@ -223,6 +223,14 @@ static cycle_t arch_counter_read(struct clocksource *cs) return arch_counter_get_cntpct(); } +int read_current_timer(unsigned long *timer_val) +{ + if (!arch_timer_rate) + return -ENXIO; + *timer_val = arch_counter_get_cntpct(); + return 0; +} + static struct clocksource clocksource_counter = { .name = "arch_sys_counter", .rating = 400, |